1. Field of the Invention
This invention relates to a breathable glove as an overglove, over a cut- and puncture-resistant and nonfuzzing underglove, for packing and sorting high-purity silicon, such as chunk polysilicon and silicon wafers.
2. Background Art
To avoid contamination of high-purity silicon in the course of manual packing and sorting, operators must wear gloves in principle. In order that glove-based contamination may be ruled out as well, gloves must ideally emit no particles when touching the silicon surface. Various measurements by manufacturers, for example KNF Clean Room Corp. and Icarus West Inc., have shown that gloves made of ultrapure polyethylene (PE) give best values in respect of particle emission per unit area for this. In this, they are far superior to other materials such as, for example, nylon, polyester, PVC, latex, polyurethane or gloves made of nitriles.
Regrettably, however, gloves made of ultrapure PE, preferably LDPE, have the disadvantage that they are not breathable and so the hands start to perspire after just a few minutes. Nor have PE gloves any cut resistance whatsoever. For this reason, safe handling of the extremely sharp silicon fragments with PE gloves requires a further, cut-resistant glove to be worn underneath.
Experience has shown that handling just a few kilograms of silicon fragments will cause the PE glove to tear and therefore require replacement. Owing to the very pronounced hand perspiration due to the PE overglove, the cut-resistant underglove likewise has to be changed after about 30 minutes.
Operators are therefore instructed to examine their PE gloves for damage at intervals of one minute. Overlooked damage risks human perspiration, which contains sodium chloride, coming into contact with the high-purity silicon and thereby rendering it unuseable. Measurements conducted in the course of the on-going operation again and again show sodium traces on the silicon fragments, attributable to perspiration from the packers and/or the sorters.
A further disadvantage with the use of PE gloves is that the perspiring in the glove can lead, long term, to permanent, irreversible skin irritation.
Various solutions for breathable or cut-resistant gloves are known from the prior art. DE-102005044839, for instance, discloses a breathable glove having a silicone palm region area for improved grip and a backside region made of an air-permeable woven fabric. US2007028356 describes a multilayered breathable glove, the inner layer of which is breathable and the outer layer of which has a high coefficient of friction to allow very secure gripping therewith. However, no prior art glove combines good breathability with minimal particle emission of the glove palm area onto the piece to be grasped.